This is quite a common problem it seems – after installing an update to Microsoft office, some of the applications will not open.
Here is one solution:
Create a temporary Windows login account with administrative rights, then log into that new account.
While logged in as the temporary user, open every Office product you have, then close one at a time (Excel, Word, Powerpoint, Project etc…)
After opening every Office application, start regedit.
(Start > Run > then type in Regedit)
Go to HKEY_CURRENT_USER > Software > Microsoft > Office, and highlight Office
Right click on Office, and select ‘Export’
Save the .reg file somewhere on your computer – note down the location...
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